Before his death in June, 1863, the novel’s Major Clayton Ellis already was planning to recover niter from bat guano in the caves around Knoxville.

His superiors in Nashville wanted it to make gunpowder for Confederate arms as the conventional sources of the propellant were increasingly being denied by the federal blockade.

Ellis was confident that the caves in the mountains around Knoxville had enough bats to keep the Confederacy supplied with niter for a thousand years if need be.

Indeed, such caves and their bats still were plentiful enough in the late 1950s to help Merlin Tuttle, the founder of Bat Conservation International, get his start on the subject when he was a teenager and living in Knoxville.